As has recently been described, there is a growing market for adaptive cruise control that is designed to either warn a driver of dangerous conditions or to actually take over the control of the car to avoid the dangerous condition. According to the National Highway and Traffic Safety Agency, dangerous conditions include road run-off, rear-end collisions, lane change and merge, and drowsy driver problems.
Various companies have instituted radar-based collision avoidance and warning systems that use relatively expensive radar units, which require consideration of RF frequency regulations and generally are not able to pinpoint the direction of an object due to the relatively wide lobes of the radar beams. Radar-based systems can therefore not reliably detect, for instance, whether an oncoming car is in the traffic lane used by the vehicle or, for that matter, detect whether or not radar returns are from a stationary target such as a tree or a road sign. Moreover, these systems are incapable of discerning the presence of individuals.
In order to compensate for the deficiencies of radar-based systems, be they laser-based or RF-based, proposals have been made to complement these systems with optical systems to analyze a scene and determine the presence of objects in the scene. These systems, however, suffer from the inability to reliably distinguish between various types of objects and require a considerable amount of computational overload.
As to backup warning systems, these systems typically employ acoustic imaging.
The result is that while there are not only collision avoidance systems, collision warning systems, adaptive cruise control systems, steer-by-wire systems, brake-by-wire systems and other automatic systems, these systems have relied principally on radar or lidar as sensors.
While lidar and radar systems do provide considerable range for the detection of returns from targets, they oftentimes result in false alarms precisely due to the range at which they operate. Moreover, the systems cannot, for instance, distinguish when an object is at car level as opposed to an overhanging sign, which may fool the system into automatically applying braking or other collision avoidance protocols such as collision avoidance steering.
It will be appreciated that if systems are employed that do more than merely alert the driver to obstacles or fast-approaching vehicles, then taking the control of the vehicle from the driver can result in serious consequences without a robust system to be able to differentiate between those objects which could cause harm to the vehicle and the occupants thereof, versus those artifacts which are not to be acted on.
There is therefore a necessity to provide a reliable and inexpensive means for establishing a protection zone around a vehicle and to provide some indication of where a particular vehicle or individual is with respect to the vehicle in question in the protection zone.
It has been reported by the National Highway Safety Agency that the number of traffic accidents can be markedly reduced when using sensors that can detect out-of-normal conditions. In such systems that use microprocessors and radars, if one can anticipate an out-of-normal condition, then one can invoke, for instance, engine controllers to retard or speed the engine towards a desired result, an ABS controller to apply or release brakes toward a desired result or to arm and deploy an airbag to prepare for impact, depending on the expected time, direction and severity of the detected potential impact.
The above-mentioned radar-based systems have been deployed front, rear and side to reduce lane change accidents and to provide advance warning to deploy airbags. Moreover, such systems have been designed to counteract unwanted turning in a panic situation.
However, all of the above systems to some extent require various forms of radar and/or an overlay of optical sensing in order to be able to reliably distinguish the type of obstacle or threat to the vehicle.
Aside from automobiles and trucks, in the military there is a need to be able, for instance, in tanks when one's vision is obscured, to detect the presence of combatants within a security perimeter of the tank. This type of situation occurs when individuals carrying satchel charges or other explosive devices sneak up to a tank unnoticed and attach or explode a device right at or on the skin of the tank. Moreover, for instance in armored vehicles such as Humvees or halftracks, a lookout is positioned at the top of the vehicle to be able to scout the perimeter of the vehicle. Additionally, tanks are sometimes provided with periscope sights and the like that have only a limited field of view and are therefore not useful in detecting close-in stealthy activity. Moreover, at nighttime there is no particularly good way to detect the presence of near-in individuals, which results in each tank or fortified vehicle having to provide for patrols to make sure that the vehicles and the occupants therein are safe.
With the adoption of IEDs, improvised explosive devices, their effective range at 3 to 5 feet is deadly and it is for this purpose that it would be desirable to provide a sensing system for such military vehicles to be able to detect the presence of intruders and to, for instance, be able to automatically actuate vehicle protective devices such as, for instance, shaped charges aimed away from the vehicle to countermeasure the intruder.
Thus, both for commercial auto safety reasons and for military security, there is a need for a sensing system that can detect the presence of individuals or objects within a protection zone around the vehicle, with the sensors providing 360° protection as well as being able to detect not only azimuth but also elevation of intruding objects.